1. Field of the Invention
The present invention relates generally to printed product collation and more particularly to a device and method for providing sheets in a stack to a conveyance device.
2. Background Information
U.S. Pat. No. 5,447,302 (xe2x80x9cthe ""302 patentxe2x80x9d) discloses an apparatus for removing paper products from a stack on a feeder, also known as a hopper. The apparatus has a rotatably mounted gripper drum which takes the bottom sheet or signature from a stack or pile of sheets. FIG. 3 of the ""302 patent shows a sheet of signatures stacked for removal by the gripper drum. A part of the sheets rests on a platform, so that a nose of the stack protrudes over the end of the platform and is restricted by a pile restrictor.
Restrictors maintain the position of the nose of the pile, prohibiting the pile from bending down over the edge of the platform. Restrictors also help prevent the second sheet or signature from being vacuumed down along with the sheet to be transferred to the gripping device.
The restrictor of the ""302 patent may inadvertently permit more than one sheet to be pulled into the gripper area, thus leading to malfunction, sheet damage, or hopper blockages. Moreover, the pile restrictor of the ""302 device may not permit adequate adjustment, which may for example be advantageous when different types of papers or other stacked products are to be transferred to a gripper drum. The ""302 patent is hereby incorporated by reference herein.
U.S. Pat. No. 2,251,943 discloses a signature gathering machine, the signatures being stacked against an abutment or wall, as shown in FIG. 2, which suffers from the same problems described with respect to the pile restrictor of the ""302 patent.
An object of the present invention is to provide a pile restrictor which permits easy adjustment of a restrictor. An additional or alternate objective is to provide a reliable and effective restrictor and related method for restricting the pile.
The present invention provides a pile restrictor for a feeder comprising a body and a restricting blade attached to the body, the restricting blade being adjustable angularly with respect to the body while the feeder is in an operating mode.
By providing the angular adjustment, the pile restrictor of the present invention can be adjusted to provide system adjustment even while the associated hopper is running, and permits for more accurate and repeatable adjustment of the restriction function of the feed device. xe2x80x9cRestricting bladexe2x80x9d as defined herein need not be a blade, but can be any object used for contacting the product nose, including but not limited to a sheet-like extension, a rod, or a bar.
Preferably, the restricting blade is also adjustable along an axis of the body, so that for example a height of the pin can be set.
The pile restrictor preferably further includes a lever arm for holding the restricting blade, the restricting blade preferably being releasable from the lever arm. A spring may be provided to operate to force the blade into an open position, with the lever arm including a flat surface. An adjusting knob acting against the flat surface and threadedly supported in the body can then be used to set the angle of the restricting blade. The adjusting knob preferably is outside of a front guide of the feeder.
The pile restrictor also preferably includes a support for supporting the body and attaching the body to the front guide of the feeder. The body preferably is slidingly adjustable within the support, so that a height of the restricting blade can be adjusted. An rotatable adjustment knob threadedly supported in the body and acting against the support can adjust the position of the body with respect to the support.
The present invention also provides a pile feeder having an operating mode comprising a front guide, and at least one pile restrictor, each of the pile restrictors connected to the front guide and including a body and a restricting blade attached to the body, the restricting blade being adjustable angularly with respect to the body during the operating mode.
The pile restrictors preferably are connected in an easily replaceable fashion, i.e. by a support plate and bolts, to the front guide. The pile restrictors also preferably are adjustable along the front guide in a direction perpendicular to the height.
The present invention also provides a method of restricting a sheet pile for a feeder comprising the steps of:
placing a pile of sheets in a feed device so that the nose of the pile is restricted by a restrictor; and
adjusting an angle of the restrictor while the feeder is in an operating mode.
Preferably the method further includes adjusting a height of the restrictor.
The present invention advantageously allows for tool-less height and angle adjustments and xe2x80x9con-the-flyxe2x80x9d adjustments, i.e. while the hopper or feeder is still running. A releasable restricting blade can permit quick replacements, as can the releasablity of the entire restrictor.